2,326. For Which Blood Is One Liable?

Maachalos Assuros 6:2

Human blood is prohibited under rabbinic law if it left the body; one is liable to stripes for acting rebelliously if he eats it. However, if one’s teeth bleed, one may swallow without hesitation. If one bites into bread and finds blood on it, he must remove the bloody part before eating it since the blood has left the body.

Maachalos Assuros 6:3

One is only liable to kareis (excision) for blood that comes out when an animal is slaughtered, killed, or beheaded that’s colored red, blood collected in an animal’s heart, and blood from bloodletting, which is blood that flows strongly. One isn’t liable for the blood that drips at the start of bloodletting before it flows strongly, or blood that drips at the end of bloodletting when the bleeding tapers off; this is like blood in the limbs (see the next halacha). Blood that flows strongly is bleeding that might cause the animal’s soul to depart.